Thermo-Electric Generator

ABSTRACT

Disclosed herein, a power supply may be recharged with a generally used system. In various embodiments, cleaning systems may be used to affect a generator to cause the generator to charge a power supply. Such charging systems may be used without the need for separate or specialized power charging systems. A charging source or system may, therefore, also charge a power supply without requiring additional steps.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. application Ser. No. 14/674,630filed on Mar. 31, 2015. The entire disclosure of the above applicationis incorporated herein by reference.

FIELD

The subject disclosure relates to power storage and generation systems,including, in various embodiments to generating and storing power forinstruments.

BACKGROUND

This section provides background information related to the presentdisclosure which is not necessarily prior art.

Instruments, including various hardware instruments, surgicalinstruments, and the like may require power sources to operate. Forexample, a surgical instrument may include a powered drill that may beelectrically powered. Additionally, various instruments may include abattery powered drill such as a rotary hammer drill. Systems associatedwith the instrument may also require power for operation that generallymay include a power source, such as a battery, that may be carried withthe instrument.

SUMMARY

This section provides a general summary of the disclosure, and is not acomprehensive disclosure of its full scope or all of its features.

Powered tools may require a power source. Also, however, certain toolsmay include additional systems that are powered in addition to thegeneral use of the tool. For example, wireless systems may be eitherbattery powered (i.e. including an on-board power system) or may bepassive (e.g. including a radiative or inductive power system).Inductive or radiative power systems can include those disclosed in U.S.Patent Application Pub. No. 2011/0237937, published Sep. 29, 2011,incorporated herein by reference.

Disclosed herein, a power source or supply, such as a battery, may berecharged with a charging system including a thermo-electric generator.In various embodiments, cleaning systems may be used to affect thethermo-electric generator to cause the generator to charge the powersource. Such charging systems may be used without the need for separateor specialized power charging systems. Further, the charge system maycharge the power source without an additional step. In other words,charging may occur within a workflow operation of the tool. Thus,charging the power source requires no additional steps to charge.

Further areas of applicability will become apparent from the descriptionprovided herein. The description and specific examples in this summaryare intended for purposes of illustration only and are not intended tolimit the scope of the present disclosure.

DRAWINGS

The drawings described herein are for illustrative purposes only ofselected embodiments and not all possible implementations, and are notintended to limit the scope of the present disclosure.

FIG. 1 is an exploded view of a tool assembly with a tracking device,

FIG. 2 is a detail view of a tool tip with the tracking device,

FIG. 3 is a workflow chart for charging a power supply, and

FIG. 4 is a view of a navigation and imaging system.

Corresponding reference numerals indicate corresponding parts throughoutthe several views of the drawings.

DETAILED DESCRIPTION

Example embodiments will now be described more fully with reference tothe accompanying drawings.

Initially, it is understood that although the following disclosurerelates to surgical instruments and various embodiments, that thedisclosure may also relate to non-surgical instruments. Generally, apowered instrument or tool may include a power pack or power supply,such as a chemical battery, to provide an energy source to power anelectrical system, such as a transmitter or sensor. Such a power sourceor storage system may be charged according to various techniques, suchas those discussed herein, regardless of the intended use of theinstrument. Therefore, it is understood that tools may be used forvarious procedures, such as a surgical procedure on a patient, includinga human patient, a mechanical assembly or repair of a non-animatesubject, or a combination thereof. In fact, it is understood thatinstruments that may be used for surgical procedures may also be usedfor non-surgical procedures.

Various instruments, such as a stylet, may include tracking devicesassociated that are tracked with an electromagnetic tracking system.Various other instruments can include drills, implants, suction devices,and the like may be used with various navigation systems such as theStealth Station® 57® navigation system sold by Medtronic, Inc., having aplace of business in Colorado, USA. Various tracking systems can includethe AxiEm® navigation system having electromagnetic fields and trackabledevices associated therewith. Generally, a trackable device may sense anelectromagnetic field and transmit information regarding the sensedfield to a tracking system. The transmission of information can be wiredor wireless, such that the tracking device is connected with a wire orwith wireless transmissions to a navigation system. Nevertheless, powermay generally be provided to the tracking device to sense the fieldand/or transmit the sensed field to the navigation system. According tovarious embodiments, a battery can be connected with the tracking deviceto provide power to sense and/or transmit the sensed field. A generator,such as a thermal electric generator, discussed here in further detail,can be used to recharge the battery and/or replace the battery toprovide power to the system transmitting the sensed field information orused to power a transmitter or an emitter, such as a coil array as usedin the AxiEM® surgical navigation system sold by Medtronic, Inc.

Regardless, and according to various embodiments, a surgical instrumentassembly 20 may be provided. A surgical instrument assembly 20 may beprovided according to various embodiments which may include one or moreattachment mechanisms 22 that are configured to couple a tool tip 24 toa tool or instrument body 26. Such systems may include those similar tothat described in U.S. Pat. No. 6,434,507, incorporated herein byreference. It is understood that the several tool assembly portions,including the tool tip 24, the attachment 22, and the tool body 26 maybe generally known in the art. However, as discussed further herein,various systems may be associated with these portions to allow fortracking of the tool assembly 20, including at least the tool tip 24. Itis also understood that various instruments can include instruments suchas those sold by Medtronic Navigation, Inc. either alone or incombination with various surgical navigation systems including theStealth Station® surgical navigation system and the AxiEm™ navigationsystem. Instruments may include navigational elements including trackingelements or devices associated with the instruments. These instrumentscan be included in the AxiEm™ navigation stylet, AxiEm™ registrationpointers, and AxiEm™ navigation probe. Further instruments can includean awl and a tap for various implants such as screws, and drills.

Nevertheless, regardless of the specific design and components of thetool assembly 20, it may include a trackable portion or device 30. Thetracking device 30 may be an assembled or connected portion, asillustrated in FIG. 1 or may be integrated as a substantiallynon-removable portion from selected components of the tool assembly 20.Further, the tracking device may be provided as one or more trackingdevices, as discussed herein. Therefore, unless specifically indicatedotherwise, discussion of a tracking device herein may refer to one ormore tracking devices associated with the tool assembly 20 or a portionthereof.

For example, a tracking device 30 may be integrated into one of theattachments 22 as tracking device 30 a. Also, the tracking device 30 maybe integrated into the tool tip 20 as tracking device 30 b. It isunderstood that the tool assembly 20 may have one or more trackingdevices, and that the illustrated tracking devices 30, 30 a, 30 b aremerely exemplary. The tracking devices may be electromagnetic trackingdevices and may be configured to be generally small in size.

For example, the tracking devices 30, 30 a, and 30 b can generallyinclude a coil of wire around an axis. The coil of wire may be around acore including a ferromagnetic core, air core, or other selected core.The tracking device 30 can be configured to be associated with arespective portion of the tool assembly to assist in tracking the toolassembly. For example to integrate or include a tracking device with astandard tool, a holder 40 may optionally be provided to connect to thetool body 26 and/or the attachments 22. The holder 40 may include aconnection region 42 that allows for connection of the tracking device30 to the holder 40. Alternatively, the tracking device 30 may beconnected directly to the tool body 26, and if selected, to have aremovable tracking device 30. Additionally, it is understood that theattachment 22 may include a plurality of attachments 22 a-e and each ofthe attachments 22 a-e can include the tracking device 30 a or arespective one of the tracking devices 30 a.

As discussed further herein, the instrument assembly, including the tooltip 24, can be tracked relative to a subject, such as a human patient,and a position of the instrument assembly, for example, including thetool tip 24, can be illustrated on a display. For example, an icon orrendering of the tool assembly 20 or only the tool tip 24 can besuperimposed on an image, such as a reconstructed image, of the subject.By tracking the tracking device, or a plurality of tracking devices, theposition of the tool assembly may be determined. Generally, it isselected to determine a location of at least a working portion 50 of thetool tip 24. The position of the working portion 50 may include boththree-dimensional coordinates (X, Y, Z), and orientation in threedegrees of freedom. These components can be used to determine a locationof the working portion 50 of the tool tip 24. It is also understood thatthe working portion of the selected instrument may include the distalend of a stylet or catheter which may not be rigidly held (i.e., thedistal portion may be flexible or moveable) relative to the tool body 26or other selected tool body.

With continuing reference to FIG. 1 and additional reference to FIG. 2,the tool tip 24 can include the tracking device 30 b. The trackingdevice 30 can include an electromagnetic (EM) tracking device includingthose disclosed in U.S. Pat. No. 8,644,907, incorporated herein byreference, and those included in the instruments used with the AxiEm™surgical navigation system instruments that are tracked with thetracking system. Briefly, the tracking device 30, including the trackingdevice 30 b, may include one or more coils 60 of conductive, such aselectrically conductive, material, such as conductive wire. If more thanone coil of wire is provided, each coil may be wound at an anglerelative to the other coils to provide a greater degree of freedominformation regarding the location of the tool tip 24.

Each of the coils 60 may be connected, such as with a conductor, to atransmission or transmitter portion 62, which may include a printedcircuit board (PCB). The transmission portion 62 may include an antenna64 that allows for wireless transmission of information to a trackingsystem and/or navigation system, as discussed further herein. Further,the transmission system 62 may include a processor to assist intransmitting the information, such as the sensed field strengths, andother appropriate processing.

Additionally, between the coils 60 and the PCB may be additionalcomponents, such as filters, amplifiers, signal processors. Also, thePCB may include additional components, such as those noted above, inaddition to the antenna. As noted herein these components and theantenna 64 may require power to transmit a signal.

A power supply or power source 66, such as a battery, may provide powerto the transmission portion 62, the coil 60, and/or other componentsincluded with the PCB or between the coils 60 and the transmissionportion 62. The PCB may further include analog circuitry (e.g.amplifiers, filters), analog to digital converters, and digitalprocessing circuitry (e.g. FPGA, DSP, discrete digital logic). Invarious examples, the digital processing circuitry may include a counterthat may determine exposure to high temperatures, such as when throughan autoclave cycle. The power source 66 can include a chemical battery,capacitor, LC tank circuit, or other appropriate energy storage portion.For example, capacitors or batteries may be charged with an externalcurrent for providing selected power to the transmission portion 62. Thepower source 66, however, may include a limited power such as enoughpower to provide transmission power during a selected procedure,including a single surgical procedure. Therefore, the power source 66may be rechargeable using an exterior current provided to the powersource 66.

An exterior source may provide the exterior current provided to thepower source 66 and this may be exterior to the tool tip 24. The currentsource may be, however, only external to the power source 66, butintegrated into the tool assembly 20, or separate from the tool assembly20. In various embodiments, a thermal electric generator 70 may beincorporated into the tool tip 24. Alternatively, the generator 70 maybe integrated and provided with or on another portion of the toolassembly 20. With the thermo-electric generator 70 incorporated into thetool tip 24 the battery 66 may be recharged after being drained orpartially drained without requiring an external (e.g., external to thetool assembly and/or the tool tip 24) source to recharge the powersource 66.

In various embodiments, the thermo-electric generator 70 may includecoupled thermo-electric electrodes which may include bismuth andtelluride (e.g. including tellurium). In the coupled electrodes, oneelectrode may be doped with palladium or selenium and the other withantimony or gold. The coupled electrodes may generate a current basedupon a temperature differential between two junctions of the electrodes.The temperature differential can be generated from an external source,such as an autoclave or steam autoclave device. Various thermo-electricgenerators can include those disclosed in U.S. Pat. Nos. 6,620,994 and4,292,579, both incorporated herein by reference. Various otherthermo-electric generators, which may be used or augmented to providethe generator 70, can include those sold by Laird, having a place ofbusiness in Earth City, Mo. or London, England. Further, the powersource 66 may include a high temperature rechargeable battery such ashose in the Thinergy Series of products, sold by Infinite PowerSolutions, having a place of business at Infinite Power Solutions,Colorado. Further, it is understood that the generator 70 can beinterconnected with the power source 66 via a charging connectioncircuitry 72. The charging connection circuitry 72 may includeregulators, etc. and may be similar to that as provided by the MaximIntegrated Power and Battery Management Series, having a place ofbusiness at San Jose, Calif. or devices sold by Watronix, having a placeof business in West Hills, Calif.

In various embodiments, therefore, the generator 70 may be used tocreate a selected current at a selected voltage to charge the battery orpower source 66. The operation of the generator 70 may be separate fromthe operation of the tracking device 30 b to determine a location of thetool tip 24. Further, it is understood, that the portions of thetracking device 30 may be separated such that the generator 70 and thepower source 66 are provided a distance from portions of the trackingdevice 30, such as the coils. For example, the generator 70 may be on adifferent component of the tool assembly 20 than the tracking coils 60.

Further, the specific make-up of the generator 70 may be optimized forselected temperature differentials that may be achieved during aselected procedure, such as an autoclaving of the tool tip 24.Therefore, charging of the power source 66 with the generator 70 mayproceed according to a method, as discussed further herein. For example,a voltage or current may be optimized to ensure that the power supply isfully or nearly fully charged during a cleaning cycle of the toolportion or assembly 20. This may consider the capacity of the powersource 66, the charging circuitry 72, etc. The tracking devices 30, 30a, and 30 b including the power source 66, generator 70, and othercomponents, may also be properly packaged for operation during aprocedure and recharging. As discussed herein, the recharging may occurin a high temperature and moisture environment. Thus, the trackingdevice 30, 30 a, 30 b may be liquid sealed, such as a hermeticallysealed, to an external environment. Due to the recharging system,including the generator 70, the seal need not be broken to recharge thepower source 66.

Turning reference to FIG. 3, a workflow or method for using the toolassembly 20, specifically and particularly using the tracking device 30associated with the tool assembly 20 is illustrated. It is understoodthat although the discussion herein refers specifically to the trackingdevice 30 b, that the discussion may related to any appropriate trackingdevice. Generally, the work flow may begin at a decision block 102 todetermine whether or not the power supply, such as the power source 66,has a proper charge. The determination may be made by transmission fromthe transmitter assembly 62 regarding a voltage of the power source 66.It is understood, however, that various other determinations may bemade. Such as a duty cycle length since a last charging cycle, etc.Also, a power source charge capacity may be determined as to whether itis properly charged, such as if it is within a selected range of aselected or predetermined optimum charge amount as measured by a voltagemeasurement, but a specific voltage measurement may vary and be selectedbased upon power consumption and/or voltage requirements for variouspurposes. If the decision block 102 determines that the charge supply isappropriate, the “yes” path 104 may be followed to prepare a navigatedtool for procedure block 106.

Preparation of the tool may include selecting the tool, assembling thetool assembly 20, or other appropriate preparation steps. For example,the particular attachment, including the attachments 22 a-22 e may beinputted to the navigation system, as illustrated further therein, toallow for the navigation system to determine a geometry and size of thetool assembly 20. Further, the preparation of the tool in block 106 caninclude ensuring the appropriate number of tools is provided for aselected procedure.

Following preparation of the navigated tool in block 106, a USE sub-workflow 105 may be entered. In the USE block 105 the tracking device 30 bmay draw current from the power source in block 108. The tracking device30 b may draw current from the power source in block 108 to communicatewith the navigation system in block 109, as illustrated in FIG. 4, inblock 110. Communication with the navigation system may be according toany appropriate communication mechanism, as discussed further herein,such as a wireless transmission. Further, the communication may includecommunicating various information that is determined or calculated by aprocessor on a tool. For example sense and emit energy may becommunicated along with logic operations, calculations regarding uses,time in operation, etc., such as in block 109. As discussed above, thepower source 66 can be connected to the transmission system 62 which mayinclude an antenna 64 to allow for transmitting a sensed field fortracking the tool tip 24. Therefore, current may be drawn from the powersource 66 to allow for communication with the navigation system in block108.

Communication with the navigation system in block 110 and drawingcurrent from the power supply in block 108 may continue as a procedureis performed with the tool assembly 20, including the tool tip 24, inblock 112. Performing a procedure in block 112 and/or completing theprocedure can include any selected procedure. For example, the tool tip24 may exemplary be a burr hole drilling tool tip that is configured toform a burr hole in a skull 150 of a subject 152, as illustrated in FIG.4. The creation of a burr hole 210 in the skull 150, however, is merelyexemplary of appropriate or possible procedures. Other procedures mayinclude placing a stent, placing a catheter, placing a deep brainstimulation probe, or the like within the subject. Further, theprocedure need not be a skull procedure or neurological procedure andmay include positioning a catheter within a vasculature of the subject,within the lungs of the subject, or other appropriate procedure.Nevertheless, during the performing of the procedure in block 112,communication with a navigation system of block 110 and a drawing ofcurrent from the power source in block 108 may occur. The current drawnin block 108 may allow the tracking device 30 b to communicateinformation regarding location to the navigation system in block 112.

Once a procedure is completed, the tool assembly, including the tool tip24, may enter a cleaning and charging sub-workflow 113. In the clean andcharging 113 the tool assembly, including the tool tip 24 with thetracking device 30 b, can be cleaned and sterilized in block 114. Invarious embodiments, cleaning and sterilizing may be performed with onlyor substantially only heat and/or steam according to generally knowntechniques. For example, heat and steam cleaning can be performed in anautoclave such as in an EZ9Plus™ fully automatic autoclave, Model 6690Sterilizer, or other sterilizers such as those sold by Tuttnauer, havinga place of business in Hauppauge, N.Y. Such sterilization systemsgenerally generate heat and/or steam to clean and sterilize items placedtherein. The cleaning and sterilization is a generally performed step ina medical setting to allow reuse of various tools and instruments. Othercleaning techniques may also heat the generator enough to cause the acurrent, but need not based solely on heat and steam. Various chemicalcleaning techniques may also heat the generator 70 enough to cause acurrent to charge the battery 66. Thus, heat and steam cleaning is notrequired.

The heat and steam generated during the cleaning in step 114 can, then,activate the thermo-electric generator 70 to generate a current duringthe cleaning and sterilizing procedure in block 116. The generatedcurrent can be collected and stored in the power source 66 in block 118.In this way, the power source 66 can be recharged after one or more usesduring a cleaning and sterilizing step in block 114. In other words, thepower source 66 may be recharged without requiring a separatecharging/recharging step. A cleaning and sterilization step may be usedto charge and/or recharge the power source 66 that is usually performedon non-disposable instruments.

Therefore, the tracking device 30 b can include a power supply that neednot be replaced after one or more uses (e.g., a disposable battery) orrecharged with a separate step and/or instrumentation. Due to theinclusion of the thermo-electric generator 70, in communication with thepower source 66 of the tracking device 30, the power source 66 can berecharged during the cleaning procedure that generally includes heatand/or steam generation. Thus allowing an efficient recharging of thepower supply for additional uses.

Following the cleaning and sterilization, the tool assembly 20 may beoptionally stored in block 120. The work flow allows for continuousrepetition and use of the tool assembly 20, as illustrated in the workflow 100 in FIG. 3. After the power is collected in the power supply inblock 118, the work flow may immediately go to the decision block ofwhether the power supply is properly charged in block 102. Following thecollection and storage of power in the power source 66 in block 118,generally the power supply is properly charged. If it is determined thatthe power supply is not properly charged, at the decision block 102, theNO path 126 may be followed to clean and sterilize, such as using heatand/or steam, in block 114. Therefore, cleaning the tool in a medicalsetting (e.g. in a hospital) may be followed to allow for regeneratingand charging the power source 66, as illustrated in the work flow 100.It is understood, however, that a specific heat-generating system thatmay be provided to charge the power source 66 via the thermo-electricgenerator 70, but is not required.

The work flow 100 allows for the use, cleaning, and recharging of thepower supply of the tracking device. The tracking device 30 b can beused with a navigation system, such as a surgical navigation system 150illustrated in FIG. 4. The navigation system 150 may be used similar toa navigation system generally known in the art, including theStealthStation® surgical navigation system sold by Medtronic, Inc.Nevertheless, the following discussion of the navigation system 150 isprovided for illustration and completeness of the current discussion.Further, it is understood that the generator 70 and power source 66 maybe provided in any appropriate device, such as the DRF tracking device271.

With reference to FIG. 4, the instrument assembly, including the toolbit 24 may be positioned relative to, such as within, the subject 150with a navigated instrument. The tool assembly 20, with the trackingdevice 30, may be a navigated instrument. As discussed above, theinstrument assembly 20 is merely exemplary, and other navigatedinstruments may include catheters, leads, stimulators, etc. Also, thetracking device 30 may incorporated into a separate element, such as aremovable stylet. The stylet may be placed within a lumen of a catheter.

The tracking device 30 may be interconnected with a navigation system202, as illustrated in FIG. 4. The navigation system, as discussedfurther herein, may include a tracking system 204 that can track thetracking device 30 in three-dimensional space including a X, Y, Zlocation and various orientations to determine a position of thetracking device 30 in space. As illustrated above, the instrument 20 mayinclude the tracking device 30 that allows for directly tracking thetool 20 during an implantation and positioning of tool 20. Appropriatetracking devices can include tracking devices as disclosed in U.S. Pat.No. 8,644,907, incorporated herein by reference. Additionally, thenavigation system can include the navigation system disclosed in U.S.Patent Application Publication 2014/0323852, incorporated herein byreference.

With continuing reference to FIG. 4, the tool 20 may be used to form anopening or bore 210 in the skull 150 of the subject 152. The bore 210may be a burr hole formed through the skull 150 as generally understoodin the art. The tool 20 may be tracked either directly via the trackingdevice 30 or via the tracking device on a stylet or other portionassociated with the tool 20. Further, as noted above, the trackingdevice may be associated directly with the tool tip 24 as the trackingdevice 30 b or with another portion of the tool assembly 20. Thus, anyone or more of these may be used to track the selected portion of thetool assembly 20.

The navigation of the tool assembly 20 relative to the subject 152 mayproceed according to various navigation procedures and techniques, suchas those generally known in the art and discussed below, to ensure orassist in positioning the catheter 10 in a selected, including apredetermined or preselected location, within the subject 152. Further,although the following description is related generally to positioningthe tool assembly 20 relative to the skull 150 of the subject 152, othernavigated procedures may be performed.

The navigation system 202, which may include an electromagneticnavigation system, is primarily described with respect to performing aprocedure on a human patient, the navigation system 202 may be used toperform a procedure on other animate and/or inanimate subjects,including those navigation systems as disclosed in U.S. Pat. App. Pub.No. 2014/0323852, incorporated herein by reference. Also, proceduresdisclosed herein can be performed relative to a volume, a mechanicaldevice, and/or an enclosed structure. The volume may be of an animate orinanimate object. The subject can be an object that includes an enclosedmechanical device.

The navigation system 202 assists in performing a navigated or guidedprocedure. The guided procedure can be, for example, a surgicalprocedure, a neural procedure, a spinal procedure, and an orthopedicprocedure. The navigation system 202 allows a user, such as a surgeon220, to view on a display 256 a position of the tool assembly 20 in acoordinate system. The coordinate system can be related to an image,such as in an image guided procedure, or can be related to an imagelessprocedure.

The navigation system 202 can operate as an image-based system or as animageless system. While operating as an imageless system, the navigationsystem 202 can register a subject space (generally defined within andnear the subject 152) to a graphical display representing an area of thesubject 152, rather than to both the subject space and an image space.Image data of the subject 152 need not be acquired at any time, althoughimage data can be acquired to confirm various locations of instrumentsor anatomical portions of the subject 152. Positions of the subject 152can be tracked and positions of the tool assembly 20 relative to thesubject 152 can be tracked.

While operating as an imageless system, a position of an anatomicalstructure can be determined relative to the instrument and the positionsof the anatomical structure and the instrument can be tracked. Forexample, a plane of an acetabulum can be determined by touching severalpoints with the tool assembly 20, or selected tracked tool with at leastone of the tracking devices 30. As another example, a position of afemur can be determined in a similar manner. The position of the toolassembly 20 and the anatomical structure can be shown on a display withicons or graphics. The display, however, may not show actual image datacaptured of the subject 152. Other data can be provided, such as atlasdata or morphed atlas data. The atlas data can be image data that isgenerated or generalized from the subject 152. For example, a brainatlas can be generated based on detail analysis of image data of a brainof a patient. Operation of the navigation system 202 as an image basedsystem is further described below.

Although the navigation system 202 is described as acquiring image datausing an imaging device 230, other data may be acquired and/or used,such as patient and non-patient specific data. The imaging device 230acquires pre-, intra-, or post-operative image data and/or real-timeimage data of a subject 152. The imaging device 230 can be, for example,a fluoroscopic x-ray imaging device that may be configured as a C-armhaving an x-ray source 232 and an x-ray receiving device 234. Otherimaging devices may be included and mounted on the imaging device 230.Calibration and tracking targets and radiation sensors may be included.

The navigation system 202 may further include an imaging devicecontroller 236. The imaging device controller 236 controls the imagingdevice 230 to (i) capture x-ray images received at the x-ray receivingsection 234, and (ii) store the x-ray images. The imaging devicecontroller 236 may be separate from the imaging device 230 and/orcontrol the rotation of the imaging device 230. For example, the imagingdevice 28 can move in selected directions around the patient 152. Also,the imaging device may include an O-arm® imaging device as sold byMedtronic, Inc., having a place of business in Minnesota.

Further, an imager tracking device 240 may be included to track aposition of selected portions of the imaging device 230 to identify theposition of the imaging device 230 relative to the subject 152 whileacquiring the image data to assist in registration. The image data canthen be forwarded from the imaging device controller 236 to a processingmodule of a navigation computer 250 wirelessly or via a link 252. Thenavigation computer 250 can include a processing module that isconfigured to execute instructions to perform a procedure.

A work station 254 can include the navigation computer 250, a navigationdisplay 256, a user interface 258, and an accessible memory system 260.The image data may be transmitted from the controller 236 to the workstation 254 or to a tracking system 204. The workstation 254 may be aportable computer, such as a laptop computer or a tablet computer. Thenavigation computer 250 including the computer module may include ageneral purpose processor that executes instructions for navigating thetool assembly 20 and/or may include an application specific circuit. Thetracking system 204, as discussed further herein, may include a coilarray controller (CAC) 260 having a navigation device interface (NDI)262.

While the imaging device 230 is shown in FIG. 4, any other alternative2D, 3D or 3D imaging acquired over time to include four dimensions,imaging modality may also be used. For example, any imaging device, suchas isocentric fluoroscopy, bi-plane fluoroscopy, ultrasound, computedtomography (CT), multi-slice computed tomography (MSCT), T1 weightedmagnetic resonance imaging (MRI), T2 weighted MRI, high frequencyultrasound (HIFU), positron emission tomography (PET), optical coherencetomography (OCT), intra-vascular ultrasound (IVUS), ultrasound,intra-operative, computed tomography (CT), single photo emissioncomputed tomography (SPECT), and/or planar gamma scintigraphy (PGS)imaging devices may be used. Any of these imaging devices may be used toacquire pre- or post-operative and/or real-time images or image data ofthe subject 152. The images may also be obtained and displayed,generally, in two or three dimensions. In more advanced forms, 3Dsurface rendering regions are achieved of the subject, which may berendered or changed in time (fourth dimension). The 3D surface renderingregions may be achieved by incorporating subject data or other data froman atlas or anatomical model map or from pre-operative image datacaptured by MRI, CT, or echocardiography modalities. Image data setsfrom hybrid modalities, such as positron emission tomography (PET)combined with CT, or single photon emission computer tomography (SPECT)combined with CT, can also provide functional image data superimposedonto anatomical data to be used to reach target sites within the subject152.

The navigation system 202 further includes the tracking system 204. Thetracking system 204 includes a localizer 264, which may also be referredto as a transmit coil array (TCA), a tracking array, or a transmit coilassembly. The TCA 264 includes coil arrays 266 that can transmit orreceive. The tracking system 204 includes the CAC 260. The localizer264, the instrument tracking device 30 of the tool assembly 20. It isunderstood that the tracked portion may be generally referred to as aninstrument and that the tracking device may be generally referred to asan instrument tracking device. The tracking system may also track adynamic reference frame (DRF) 270. All tracked portions are connected tothe CAC 260 via the NDI 262. The CAC 260 and the NDI 262 can be providedin a CAC/NDI container 272. The NDI 262 may have communication portsthat communicate with the localizer 264, the instrument tracking device30 and/or the DRF 270 wirelessly or via wires.

The coil arrays localizer 270 can transmit signals that are received bythe DRF 270 and at least one tracking device (e.g., the instrumenttracking device 30). The tracking device 30 can be associated with thetool assembly 20 at a location that is generally positioned within thesubject 152 during a procedure. The DRF 270 can then transmit and/orprovide signals, from a DRF tracking device 271, based upon thereceived/sensed signals of the generated fields from the localizer 270and/or other localizers. It is understood that the tracking system mayalso be operated in reverse, where the tracking devices 30, 270 transmita field that is sensed by the TCA 270.

The DRF 270 can be connected to the NDI 262 to forward the informationto the CAC 260 and/or the navigation computer 250. The DRF 270 may befixed to the subject 152 and adjacent to the region where navigation isoccurring such that any movement of the subject 152 is detected asrelative motion between the localizer 264 and the DRF 270. The DRF 270can be interconnected with the subject 152. Any relative motion isindicated to the CAC 260, which updates registration correlation andmaintains accurate navigation.

In operation, the navigation system 202 creates a map between points inimage data or an image space, such as one defined by an image 280 shownon the display 256, and corresponding points in a subject space (e.g.,points in an anatomy of a patient or in a patient space). After the mapis created, the image space and subject space are registered to eachother. This includes correlating position (location and orientations) inan image space with corresponding positions in a subject space (or realspace). Based on the registration, the navigation system 202 mayillustrate an icon 282 (which may include a three-dimensional renderingof the instrument, including the tool assembly 20) at a navigatedposition of the tool assembly 20 relative to an image of the subject 152in a super-imposed image. For example, the icon 282 can be illustratedrelative to a proposed trajectory and/or a determined anatomical target.The work station 254 alone and/or in combination with the CAC 260 and/orthe C-arm controller (or control module) 236 can identify thecorresponding point on the pre-acquired image or atlas model relative tothe tracked tool assembly 20; and display the position on display 256and relative to the image 280. This identification is known asnavigation or localization. The work station 254, the CAC 260, and theC-arm controller 236 and/or selected portions thereof can beincorporated into a single system or implemented as a single processoror control module.

To register the subject 152 to the image 280, the user 220 may use pointregistration by selecting and storing particular points from thepre-acquired images and then touching the corresponding points on thesubject 152 with a pointer probe or any appropriate tracked device. Thenavigation system 202 analyzes the relationship between the two sets ofpoints that are selected and computes a match, which allows for acorrelation of every point in the image data or image space with itscorresponding point on the subject 152 or the subject space.

The points that are selected to perform registration or form a map arethe fiducial markers, such as anatomical or artificial landmarks. Again,the fiducial markers are identifiable on the images and identifiable andaccessible on the subject 152. The fiducial markers can be artificiallandmarks that are positioned on the subject 152 or anatomical landmarksthat can be easily identified in the image data.

The navigation system 202 may also perform registration using anatomicsurface information or path information (referred to asauto-registration). The navigation system 202 may also perform 2D to 3Dregistration by utilizing the acquired 2D images to register 3D volumeimages by use of contour algorithms, point algorithms or densitycomparison algorithms.

In order to maintain registration accuracy, the navigation system 202tracks the position of the subject 152 during registration andnavigation with the DRF 270. This is because the subject 152, DRF 270,and localizer 264 may all move during the procedure. Alternatively thesubject 152 may be held immobile once the registration has occurred,such as with a head holder. Therefore, if the navigation system 202 doesnot track the position of the subject 152 or an area of an anatomy ofthe subject 152, any subject movement after registration would result ininaccurate navigation within the corresponding image. The DRF 270 allowsthe tracking system 204 to track the anatomy and can be used duringregistration. Because the DRF 270 is rigidly fixed to the subject 152,any movement of the anatomy or the localizer 264 is detected as therelative motion between the localizer 264 and the DRF 270. This relativemotion is communicated to the CAC 260 and/or the processor 250, via theNDI 262, which updates the registration correlation to thereby maintainaccurate navigation.

The tracking system 204 can position the localizer 270 adjacent to thepatient space to generate an EM field (referred to as a navigationfield). Because points in the navigation field or patient space isassociated with a unique field strength and direction, the trackingsystem 204 can determine the position (which can include location andorientation) of the tool assembly 20 by measuring the field strength anddirection or components of the EM field at the tracking device 30. TheDRF 270 is fixed to the subject 152 to identify the location of thesubject 152 in the navigation field. The tracking system 204continuously determines the relative position of the DRF 270 and thetool assembly 20 during localization and relates this spatialinformation to subject registration data. This enables image guidance ofthe tool assembly 20 within and/or relative to the subject 152.

To obtain a maximum accuracy it can be selected to fix the DRF 270 ineach of at least six degrees of freedom. Thus, the DRF 270 or anytracking device, such as the tracking device 30, can be fixed relativeto axial motion X, translational motion Y, rotational motion Z, yaw,pitch, and roll relative to a portion of the subject 152 to which theDRF 270 is attached. Any appropriate coordinate system can be used todescribe the various degrees of freedom. Fixing the DRF 270 relative tothe subject 152 in this manner can assist in maintaining maximumaccuracy of the navigation system 202.

The tool assembly 20 can include the stylet, drill, etc., as discussedabove. Thus, reference to the tool assembly 20 is not intended to limitthe instrument that may be tracked and navigated. With reference to anyappropriate navigated instrument, it may include the tracking device 30that may include the power source 66 and generator 70. The power supplymay be charged, as discussed above, and the tool may be tracked with thenavigation system as discussed above.

Further, it is understood that the power source 66 and the generator 70may be provided with any appropriate powered device. An implantablemedical device may include the thermo-electric generator 70 connected tothe power source 66. For example, an IMD may include a cardiacstimulator or neural stimulator that includes a power source to providestimulation and rhythm regulation. The power source may be drained overtime when providing the selected stimulation and rhythm regulation.Temperature differentials within a selected subject may be used togenerate a current with the thermo-electric generator 70 therein.

The wireless communications described in the present disclosure can beconducted in full or partial compliance with IEEE standard 802.11-2012,IEEE standard 802.16-2009, IEEE standard 802.20-2008, and/or BluetoothCore Specification v4.0. In various implementations, Bluetooth CoreSpecification v4.0 may be modified by one or more of Bluetooth CoreSpecification Addendums 2, 3, or 4. In various implementations, IEEE802.11-2012 may be supplemented by draft IEEE standard 802.11ac, draftIEEE standard 802.11ad, and/or draft IEEE standard 802.11ah.

Example embodiments are provided so that this disclosure will bethorough, and will fully convey the scope to those who are skilled inthe art. Numerous specific details are set forth such as examples ofspecific components, devices, and methods, to provide a thoroughunderstanding of embodiments of the present disclosure. It will beapparent to those skilled in the art that specific details need not beemployed, that example embodiments may be embodied in many differentforms and that neither should be construed to limit the scope of thedisclosure. In some example embodiments, well-known processes,well-known device structures, and well-known technologies are notdescribed in detail.

The foregoing description of the embodiments has been provided forpurposes of illustration and description. It is not intended to beexhaustive or to limit the disclosure. Individual elements or featuresof a particular embodiment are generally not limited to that particularembodiment, but, where applicable, are interchangeable and can be usedin a selected embodiment, even if not specifically shown or described.The same may also be varied in many ways. Such variations are not to beregarded as a departure from the disclosure, and all such modificationsare intended to be included within the scope of the disclosure.

What is claimed is:
 1. A method of power an instrument, comprising:operating an instrument to draw power from a power source; and cleaningthe instrument with heat to at least charge the power source with aprovided thermo-electric generator when exposed to a selectedtemperature differential between a first contact and a second contact ofthe thermo-electric generator.
 2. The method of claim 1, wherein heatcleaning the instrument includes simultaneously sterilizing theinstrument and charging the power source.
 3. The method of claim 1,further comprising: preparing the instrument for a procedure includingdetermining whether the power source has a predetermined charge.
 4. Themethod of claim 1, further comprising: providing the instrument toinclude at least a tracking sensor operably connected to thethermo-electric generator; wherein the power source powers the trackingsensor.
 5. The method of claim 4, further comprising: drawing a currentfrom the power source to operate the tracking sensor for tracking theinstrument.
 6. The method of claim 1, further comprising: operating alocalizer to emit an electromagnetic field to be sensed by a trackingdevice powered by the power source.
 7. The method of claim 6, furthercomprising: providing the tracking device to include at least a coil ofconducting material to sense the emitted electromagnetic field.